Sweden investigating 19 Salmonella illnesses

Between 15 and 28 July, 19 cases of Salmonella Typhimurium have been reported to Folkhälsomyndigheten (the Public Health Agency) from the southern part of the country.

The source is unknown with interviews attempting to see what the cases have in common in terms of food intake and travels.

The median age of cases is 33 years and the majority are men (63%).

Ongoing investigation​

Folkhälsomyndigheten told us it did not yet know if the outbreak is over and would wait until three times the maximum incubation period has passed to be safe (the end of next week).

The agency said it is collecting more information from the cases, monitoring suspected new cases and typing isolates.

It stressed the importance of having a general good hygiene and following the recommended food hygiene routines to avoid growth of the bacteria.

The outbreak strain has MLVA profile 3-15-N-N-311 and a few cases with this profile are usually seen around summertime every year.

It was brought to the attention of the agency as typing of isolates showed an unusually large number of cases with the specific MLVA-profile.

Reported to EPIS and other involved agencies​

The outbreak has been reported in the Epidemic Intelligence Information System (EPIS) but no other country seems to be affected.

Livsmedelsverket (the National Food Agency) said at this stage Folkhälsomyndigheten is in charge of the investigation.

It would be responsible for traceback in the chain when and if suspected food vehicles are identified.

The cause of cases is also under investigation by the Statens veterinärmedicinska anstalt (National Veterinary Institute).

Earlier this year in a separate outbreak, Salmonella Typhimurium led to at least 39 illnesses with a link to sausage. The first date of reported illness was March 10 and the last was April 10.

A link was made through interviews and a case-study based on trawling questionnaires and sampling of the sausage.